[Info-vax] NaT consumption faults with COBOL?

[John Reagan]

"Jim Duff" <spam.this at 127.0.0.1> wrote in message 
news:49dbt6-ddk.ln1 at SendSpamHere.ORG...
> All,
>
> I'm currently seeing some NaT consumption faults on straight COBOL code
> compiled with HP COBOL V2.9-1453 on OpenVMS IA64 V8.3-1H1.  The compiler
> is invoked with the following qualifiers:
>
> /ansi/tie/standard=v3/reserved=noxopen/check=(all,nodec)/convert=leading
>
> Looking up the NATFAULT error, we have (in part):
>
> "A NaT value can be generated by a user program using an I64 feature
> called control speculation. However, compiler-generated code should
> never take a NaT fault."
>
> Based on this, a call was logged with HP, and they came back with "This
> is a function of the memory load on your machine."
>
> This doesn't ring right with me.  Has anyone else seen anything similar?
> Any known issues around this area?
>

That wasn't the most helpful answer you received.

I haven't seen any NaT consumption faults with COBOL code.  There was some 
bugs in the GEM code generator that might expose incoming NaT that just 
happen to be sitting around in registers.  We only saw them in C and BLISS 
code.  However, my memory says they should be fixed in the GEM inside of 
COBOL V2.9 regardless.

Is this easily reproducable?  Most NaT consumption faults I've seen are 
random and hard to pin down.

You should submit a case against the COBOL compiler and provide a reproducer 
if possible.  If not, the team would certainly want to know enough info to 
track it back to the COBOL source line that tripped across the NaT (so .MAP 
files, /LIST/MACH files, etc.).  We need that to figure out which code 
pattern needs NaT safety checking.  As the message said, no 
compiler-generated code should take a NaT fault (including Macro-32).  You 
should only be able to get a NaT fault if you write in Itanium assembly and 
aim at your foot.

GEM itself does not use the NaT feature of Itanium, but the C++ compiler 
does (which is how NaT show up from time to time).

I can explain in more detail if folks are interested (and you have a strong 
gag reflex).

John